1. Field of the Invention
The present invention relates to a plasma generator, and more particularly to a small-sized microwave plasma generator capable of generating plasma with low electric power.
2. Description of the Background Art
A plasma torch is a device that generates a directed flow of plasma from its nozzle. The plasma jet can be used to melt a solid, or evaporate a solid or a liquid, or heat a gas to increase enthalpy in a closed thermodynamic system under constant and entropy.
A conventional microwave plasma generator, usually equipped with a magnetron, consumes more than 100 watts to operate. A conventional microwave plasma generator, equipped with a rectangular waveguide, is too bulky to carry. A coaxial microwave plasma torch, equipped with an antenna-shaped discharge tube may substitute for the conventional microwave plasma generator, but is also too large-sized to carry.
The conventional microwave plasma generator is currently in use which generates plasma at atmospheric pressure, using various types of electric power sources. A great deal of research has gone into developing a microwave plasma generator which generates plasma without thermal effect with low electric power by using a microwave with a frequency of 900 Mega Hertz or 2.45 Giga Hertz.
Worldwide research has been done on application of plasma to the biomedical field. The U.S. FDA approved the use of the microwave plasma generator in medical treatment of wrinkles and speckles on the human skin. Development of a portable microwave plasma generator consuming less than 5 watts at atmospheric pressure will expand its application to cancer treatment, dental care, cosmetic treatment, disinfection, coagulation, sterilization, air purification, and so forth.